Carbonic anhydrases are zinc-containing enzymes which catalyze reversible reaction of carbon dioxide hydration. These enzymes participate in essential physiological processes related to respiration, CO2/bicarbonate transport between lungs and metabolizing tissues, pH and CO2 homeostasis, electrolyte secretion in many tissues/organs, etc. To date there are 15 carbonic anhydrase (CA) isozymes identified in humans—12 catalytically active and 3 inactive, so called carbonic anhydrase related proteins. The 12 active isoforms have different subcellular localization—5 of them are cytosolic, 4—membrane bound, 2 mitochondrial and 1—secreted. The major class of carbonic anhydrase inhibitors is aromatic and heterocyclic inhibitors possessing sulfonamide group. Sulfonamide-class carbonic anhydrase inhibitors are widely used as therapeutic agents for treatment of various diseases, since the 15 carbonic anhydrase isozymes are widely distributed in most of the cells, tissues and organs where they are responsible for essential physiological functions. Another similar protein class is metalloproteinases, proteolytic enzymes, which are characterized by increased expression during various steps of cancer progression. Sulfonamide inhibitors have a great potential for the inhibition of metalloproteinases.
Carbonic anhydrases participate in many essential physiological processes, therefore the increased activity or expression of different CA isoforms results in significant pathological outcomes. Therefore the regulation of CA catalytic activity by means of inhibition or activation proposes a therapeutic perspective.
There are several diseases with the characteristic disbalance of the interconversion between carbonic dioxide and bicarbonate resulting in pH alteration, disturbance of ion transport, fluid secretion, etc. CA activators may have pharmacological applications in pathologies in which learning and memory are impaired, such as Alzheimer's disease or aging (Temperini, C. et al. (2009), Drug Design of Zinc-Enzyme Inhibitors: Functional, Structural, and Disease Applications; Eds.: Supuran, C. T. and Winum, J.-Y., Wiley: Hoboken, N.J., p 473). While most often carbonic anhydrase inhibitors are used as antiglaucoma agents, they are also employed for treatment of another diseases: retinal and cerebral edema (inhibitors of CA I) (Gao, B. B. et al. (2007), Nat. Med. 13, 181), altitude sickness (inhibitors of CA II) (Basnyat, B. et al. (2003), High Alt. Med. Biol. 4, 45), epilepsy (inhibitors of CA II, CA VII, CA XIV) (Hen, N. et al. (2011), J. Med. Chem. 54, 3977). Few novel synthesized inhibitors of CA VA, CA VB, CA XII and CA IX are undergoing clinical investigation as antiobesity and antitumor drugs or diagnostic tools (De Simone, G. et al. (2008), Curr. Pharm. Des. 14, 655; Guler, O. O. et al. (2010), Curr. Med. Chem. 17, 1516). It was identified that CA inhibitors suppress the growth of leukemia, melanoma, lung, ovarian, colon, kidney, prostate, breast, and CNS cancer cells (Supuran, C. T. et al. (2000), Eur. J. Med. Chem. 35, 867; Guler, O. O. et al. (2010), Curr. Med. Chem. 17, 1516; De Simone, G. et al. (2010), Biochim. Biophys. Acta, 1804, 404; Battke, C. et al. (2011), Cancer Immunol. Immunother. 60, 649). Namely, the carbonic anhydrases IX and XII are directly related to cancer development. The use of CA IX-specific inhibitor set for detection and treatment of pre-cancer and neoplastic state is described (WO 2004/048544). There are a few reports about CA XIII involvement in the sperm mobility processes (probably together with CA XIV). Inhibition of these two CAs may be used in obtaining contraceptive agents (Lehtonen, I. et al. (2004), J. Biol. Chem. 279, 2791). It was established that CA inhibitors are useful diuretics for the treatment of patients which suffer from edema and heart deficiency. It is supposed that inhibition of the CA II activity could be useful for the diminishment of the bone resorption. It was shown in prokaryotes that the carbonic anhydrases are essential for respiration, carbon dioxide transport and photosynthesis. Therefore it was hypothesized that carbonic anhydrase inhibitors could be used as antibiotics. Ethoxzolamide was even used for the treatment of meningitis. It was noticed that carbonic anhydrase inhibitors possess an antimallarial activity. (Merlin, C. et al. (2003), J. Bacteriol. 185, 6415; Pastorekova, S. et al. (2004), J. Enzyme Inhib. Med. Chem. 19, 199; WO 2005/107470).
Introduction of fluorine atom as substituent in various positions of the benzene ring of benzenesulfonamides was investigated from point of view as CA inhibition. Pentafluorobenzenesulfonamide was described as bCAII inhibitor (Olander, J. et al. (1973), JACS, 95, 1616; Krishnamurthy, V. M. et al. (2007), Chem. Asian J. 2, 94). As far as known to the authors of this invention, there are no mention in the literature about 4-substituted-2,3,5,6-tetrafluorobenzenesulfonamides activity towards CA inhibition. Such compounds bearing cycloalkylamino or alkylamino groups in 4-position were described as anticonvulsants (GB 1031082, BE 659230 (original)). The compound 4-methoxy-2,3,5,6-tetrafluorobenzenesulfonamide was described as anticonvulsant too (GB 1025314, BE 664831). The compounds 4-piperonyl-2,3,5,6-tetrafluorobenzenesulfonamide and 4-(cyclohexylamino)-2,3,5,6-tetrafluorobenzenesulfonamide was mentioned in article about detection of sulfonamido groups (Bradshaw, L. R. A. (1969), Journal of Chromatography, 44, 422). The synthesis of 4-methoxy- and 4-amino-2,3,5,6-tetrafluorbenzensulfonamides was described (Robson, P. et al. (1963), J. Chem. Soc. 3692). The synthesis of non substituted 2,3,5,6-tetrafluorbenzensulfonamide was described in the same article. As far as known to the authors of this invention, there are no mention in the literature about 2,4-disubstituted-3,5,6-trifluorobenzenesulfonamides and 3,4-disubstituted-2,5,6-trifluorobenzenesulfonamides. The compounds 2-substituted-3,5,6-trifluorobenzenesulfonamides have not been investigated as CA inhibitors according to authors of this invention. It is known only that compound 2-cyclopropylamino-3,5,6-trifluorobenzenesulfonamide was used for preparation of benzothiadiazine derivatives, which were used as AMPA receptor modulators (WO 2010004139). The synthesis of non substituted 2,3,5-trifluorobenzenesulfonamide, 2,3,4-trifluorobenzenesulfonamide, 2,3,6-trifluorobenzenesulfonamide and 2,4,6-trifluorobenzenesulfonamide and their use for preparation of benzothiadiazine derivatives was described in the same patent. Preparation of pyrazolylbenzothiazoles bearing fragment of 2,3,4-trifluorobenzenesulfonamide and their use as inhibitors of integrin-linked kinase was described (WO 2004011460). The synthesis of 2,3,4-trifluorobenzenesulfonamide and use as intermediate compound for preparation of 2,3-difluorobenzensulfonamide derivatives was described in another patent (WO 2008017932). These derivatives were investigated as CA inhibitors. As far as known to the authors of this invention, there are no mention in the literature about 3,4,5-trisubstituted-2,6-difluorobenzenesulfonamides. Other substituted difluorobenzenesulfonamides are investigated vaguely as CA inhibitors. Derivatives of 2,3-difluorobenzensulfonamide were described in patent (WO 2008017932). Such fluorinated benzenesulfonamides as non substituted 2,6-difluorobenzenesulfonamide and 3,5-difluorobenzenesulfonamide were investigated for the same reason (Krishnamurthy, V. M. et al. (2007), Chem. Asian J. 2, 94). The compound 5-(aminosulfonyl)-2,3-difluorobenzoic acid was described as intermediate compound for preparation of mono fluorinated substituted benzenesulfonamides as CA inhibitors (Vernier, W. et. al. (2010), Biorg. Med. Chem. 18, 3307). But there are a lot of data about substituted difluorobenzenesulfonamides bearing fluorine atoms in different positions and their use for different purposes than CA inhibition. 4-Substituted-2,3-difluorobenzenesulfonamides were intermediates for preparation of benzothiadiazine derivatives, which were used as AMPA receptor modulators (WO 2010004139). Substituted 2,3-difluorobenzenesulfonamides were investigated as prostaglandin E synthase-1 inhibitors (US 20090163586), matrix metalloprotease inhibitors (WO 2009118292). Substituted 2,4-difluorobenzenesulfonamides were intermediates for preparation of benzothiadiazine derivatives, which were used as AMPA receptor modulators (WO 2010004139). Substituted 2,4-difluorobenzenesulfonamides were investigated as mGluR2 antagonists (WO 2007110337, WO 2006099972), TRPV1 inhibitors (US 20080146637), CCR5 antagonists (WO 2004054974), prostaglandin E synthase-1 inhibitors (US 20090163586). Substituted 2,5-difluorobenzenesulfonamides were intermediates for preparation of benzothiadiazine derivatives, which were used as AMPA receptor modulators (WO 2010004139). Substituted 2,5-difluorobenzenesulfonamides were investigated as dipeptidyl peptidase IV inhibitors (CN 101418001). Substituted 2,6-difluorobenzenesulfonamides were intermediates for preparation of benzothiadiazine derivatives, which were used as AMPA receptor modulators (WO 2010004139). Substituted 3,4-difluorobenzenesulfonamides were intermediates for preparation of benzothiadiazine derivatives, which were used as ATP-Sensitive Potassium Channel Openers (de Tullio, P. et. al. (2005), J. Med. Chem. 48, 4990). Substituted 3,4-difluorobenzenesulfonamides were intermediates for preparation of N-(phenylsulfonyl)benzamides and N-(3-pyridylsulfonyl)benzamides as apoptosis-inducing agents for the treatment of cancer and immune diseases and autoimmune diseases (US 20110124628). Substituted 3,4-difluorobenzenesulfonamides were investigated as prostaglandin E synthase-1 inhibitors (US 20090163586), CCR5 antagonists (WO 2004054974). Substituted 3,5-difluorobenzenesulfonamides were intermediates for preparation of N-(phenylsulfonyl)benzamides and N-(3-pyridylsulfonyl)benzamides as apoptosis-inducing agents for the treatment of cancer and immune diseases and autoimmune diseases (US 20110124628). Substituted 3,5-difluorobenzenesulfonamides were investigated as prostaglandin E synthase-1 inhibitors (US 20090163586), TGR5 agonists (WO 2010093845, WO 2011071565), for treatment of cancer (WO 2011029842). Substituted 3,6-difluorobenzenesulfonamides were investigated for preparation of substituted imidazolidine-2,4-diones (WO 2008017381).
Despite the fact that a large number of different sulfonamides have been synthesized to date, the available pharmaceutical agents created on the basis of these sulfonamides have a number of shortcomings. One of the main shortcomings is the non-selective inhibition of all carbonic anhydrases throughout the whole human body. This results in various unexpected side effects, mostly because of non-specific inhibition of all CA isoforms and their toxicity.
Presently clinically used CA inhibitors, when acting non-specifically, cause a number of side-effects. Especially toxic are systemic inhibitors. They cause electrolyte disbalance, drowsiness, head-ache, depression, apathy, malaise, irritability, nervousness, fatigue, gut irritability, anorexia, nausea, thirst, obstruction, muscle weakness, tremor, hyper- and hypoglycemia, kidney pain, disuria, bone marrow depression, metabolic acidosis and other.
Therefore, the creation of isoform-specific or organ-selective sulfonamide inhibitors is still an important task.
Invented compounds show great possibility to synthesize fluorinated benzenesulfonamides bearing different substitutes in o, m, p positions according to sulfonamide group. Presence of fluorine atoms in such compounds exerts an acidifying effect on the sulfonamide protons, which correlates with an increase in the CA inhibitory properties. These features enable good possibilities to create isoform-specific sulfonamide inhibitors.